In the past incineration of waste organic sludge has been a problem even in a pelletized form due to the inability of a self contained combustion process to compensate for wide variations in quality of fuel feedstock. It has been difficult to generate sufficient heat continuously during the combustion process to vaporize the fuel high moisture content. Sufficient heat at levels suitable for fuel pre-ignition drying has not been available. Unstable conditions have resulted in variations in furnace temperatures which permit formation of deleterious products of combustion.